Half-Life 2 took 6 years to build, and here almost 6 years later we get to release it again - this time on the Mac. As of today Half-Life 2, Half-Life 2: Episode 1, and Half-Life 2: Episode 2 are available on Steam on the Mac. They're SteamPlay titles, so if you own the games on the PC you already get them on the Mac, and if you haven't played HL2, buying it gets you access on both systems. Half-Life 2 has one of the highest critical ratings of any Valve game, with a 96 on Metacritic, and has seen consistently high player numbers on Steam with over 216,000 users playing it in the last month.

So to give everyone an excuse to play through them again, we've added Steam Achievements to Half-Life 2 and Episode 1, for both the Mac and PC versions. 32 achievements for Half-Life 2, and 13 achievements for Half-Life 2: Episode 1 (Episode 2 already had achievements).

To make sure you never lose your progress, your save games will now be stored in the Steam Cloud automatically each time you exit the game. If want to upload existing save games to the cloud, just launch the game and then exit. The Steam Cloud will store your most recent 100MB of save files - each save game, once compressed, takes around 2MB so that's around 50 save files. We've spent a lot of time racking server boxes crammed with hard-drives, so please take advantage!

The best part is that even the save games are Steam Play - you can take your PC save games and use them on the Mac. To demo this feature, we've got Alfred, the Mac team lead, showing off his work by starting a game of HL2 on the PC and then continuing it on his Mac: